Vapor separating pump



Oct. 29, 1957 M. L. EDWARDS 2,811,110

VAPOR SEPARATING PUMP 2 Sheets-Sheet 1 Filed June 19. 1951 29 f g i l 25 52 ZHVEHL UF-V ZZg'lealowgZ/Zdwazds Oct. 29, 1957 M. L. EDWARDS 2,811,110

VAPOR SEPARATING PUMP Filed June 19, 1951 2 Sheets-Sheet 2 l J 44 fi 46a 4 fi 46a: f VEJYZ 0P 45 Miles liowgglidwardfi United States Patent 9 VAPOR SEPARATING PUMP Miles Lowell Edwards, Portland, Oreg.

Application June 19, 1951, Serial No. 232,406 4 Claims. (Cl. 103-113) This invention relates to a diffusion type vapor separating pump having a mixed flow impeller which separates gases and vapors from liquids being pumped and propels the separated gases and vapors through slots or ports in the hub thereof.

Specifically, the invention deals with a submerged type electric motor and booster pump unit having an open ended impeller chamber surrounded by an annular pumping chamber and equipped with an impeller having a per'ipherally slotted hub in one open end of the impeller chamber together with a ring of mixed flow pumping vanes defining vapor separating chambers therebetween which are vented to the outside of the pump through the slots in the hub.

A feature of this invention resides in the provision of a shallow throat at the vapor diffusing end of the pump casing for coacting with the tub of the impeller to diffuse vapor rich material out of the pump.

Another feature of this invention resides in the provision of an impeller with a concave hub portion to create a pumping eflect in the diffusion throat of the pump.

According to this invention, materially increased pumping capacity is obtained by providing a novel vapor removing outlet for a booster pump. This outlet includes a diverging throat in the top end of the pump casing receiving the multi-diameter hub of a vapor separating impeller. The large diameter hub portion has relatively close running clearance relationship with the opening in the top of the impeller chamber of the pump casing and is peripherallyslotted or notched to provide ports. These ports provide top vents for vapor separating chambers which are defined between the pumping vanes in the impeller chamber. A ring of such vanes depend from the hub to the inlet of the pump and are of the mixed flow type with helically pitched inner ends and tangential outer ends. The smaller diameter portion of the hub is concavely curved for coacting with the throat to create a pumping effect which sweeps the vapor rich material out of the ports and away from the open end of the pump. The inner ends of the vanes are helically pitched so as to have an axial flow action on the fluid. This causes the vapor rich material which collects at the central portion of the impeller to be forced under positive pressure through the ports. The vapor separating chambers, however, communicate freely with outer centrifugal pumping chambers between the tangential outer ends of the vanes and these pumping chambers discharge into the volute or annular pumping chamber which surrounds the impeller chamber. The leading ends of the vanes at the pump inlet preferably have a very flat pitch to gradually accelerate the liquid entering the inlet. The leading edges of these leading ends are preferably arranged in diametrically aligned pairs. Four vanes in two diametrically opposed pairs have been found exceptionally satisfactory.

It is, then, an object of this invention to provide a dif fusion type vapor separating pump with a novel vapor removing outlet fed by ports in the impeller hub and hav- Patented Oct. 29, 7-

ing a swirl chamber which rapidly dissipates the vapor rich material out of the ports and away from the pump.

Another object of the invention is to provide a. pump with a diffusion outlet having a diverging throat and a plu-. rality of rotating ports discharging into the throat under the influence of axial and centrifugal forces respectively created on opposite sides of the throat.

A still further object of the invention is to providean improved impeller for vapor separating pumps which induces discharge of vapor rich material through rotating ports in a diffusion outlet of a pump. 1 i

Another object of the invention is to provide a vapor separating pump impeller with a single set of mixed flow vanes having helically pitched inner endsand upstanding centrifugal pumping vanes connected to the helically pitched inner ends through radially offset portions wherein the helical inner ends are relatively flat pitched at their enrtance edges to gradually accelerate liquids in an axial direction as the liquids are thrown centrifugally outward under the influence of the pumping vanes.

A specific objectof the invention is to provide. animproved diffusion outlet for vapor separating pumps wherein a concave arcuate hub portion of an impeller operates in a diverging throat to coact with the throat for creating a swirl chamber that will sweep vapors out of the pump.

Other and further objects of the invention will be apparent to persons skilled in the art from the following detailed description of the annexed sheets of drawings which, by way of a preferred example only, illustrateone embodiment of the invention.

On the drawings: I

Figure l is a vertical cross-sectional view, with parts in elevation, of a diffusion type vapor separating pump and motor unit for submerged mounting in a tank such as an aircraft fuel cell. I

Figure 2 is a top plan view of the impeller of the pump of Figure l. V

Figure 3 is an enlarged fragmentary vertical cross sec.- tional view of the impeller and pumping chamber of the pump of Figure l. 4

Figure 4 is a side elevational view of the impeller of the pump of Figure 1.

Figure 5 is an enlarged bottom plan view of the impeller.

Figure 6 is a transverse section with parts in plan viewed along the line VIVI of Figure 3. i

As shown on the drawings:

The pump and motor unit 10 of Figure 1 is especially adapted for submerged vertical mounting in a tank such as an aircraft fuel cell and has a base 11 with a peripheral flange 11a therearound for underlying the bottom wall of a fuel cell to be secured thereto in sealed relation therewith so that the unit will project vertically into the cell. The base 11 is integral with a pump casing 12 defining an annular volute chamber 13 surrounding an open ended impeller chamber 14. The volute 13 discharges through a tangential outlet 15 into an upstanding tubular portion 16 on the base 11. The tubular portion 16 provides an open ended discharge passageway, one end of which is adapted to be closed by a cap 17 and the other end of which is adapted to receive an elbow fitting 18. The cap 17 and fitting 18 are clamped on opposite ends of the tubular member 16 by means of a bolt 19. The cap and 'fitting can be reversed, if desired. In aircraft installations, liquid fuel from the volute 13 is discharged through the outlet 15 and fitting 18 into the fuel conduit (not shown) leading to an aircraft engine driven main fuel pump which supplies the engine carburetor.

The base 11 surrounds a sump S thebottom of which is closed by a detachable cover 20 secured to the base by means of fastening screws such as 21 and having a central drain outlet boss 22 closed by a plug 23. Liquid from the tank can flow freely into the sump S to cover throat ring 24- is securedto the pumpcasing 12- and projects into the chamber 14 to provide an inlet at the, bottom end of thechamb'er and a diverging side wall 26in the chamber. The side wall 26 extends-from a fiat horizontal rim or shoulder 27*surrounding the inlet 25to a dart rim end '28 flush with the loweredge of the annular gap 29' which joins thechamber 14 with the volute 13". The throatring is secured to the" casing by means of cap screws such. as 3tl'which extend through a peripheral flange'31' underlying the pump casing and surrounding the throat ring. 7

The pump casing has a flat horizontal end wall 32 at the top'end' of the impeller chamber 1'4 and this end wall forms the upper edge ofthe' gap '29 between the chamber 14 and the volute 13. A circular aperture 33 forms a diffusion outlet for the top of the chamber 14 and extends vertically upward fromfthe wall 32 to a divergin throat wall" 34 providin a tapered diffusion throat 35 in the top end of the casing 12.

Upstan'ding posts 36 and 37 on the casing 12 support an end head 38 for an electric motor mounted in a cylindrical container or housing 39. The motor has an armature driven shaft 40depending through the head 38. Shaft seal structure 41 is mounted in the head 38 by means of a retainer sleeve 42 which is threaded into the bottom end of the head.

The motor shaft '40 depends from the head 38 into the central portion of the impeller chamber 14 and an impeller 43 has a hub 44 secured on the shaft in any suitable manner, for example bymeans of a nutand key.

The hub 44 includes a relatively shallow large diameter portion 45 projecting through the aperture 33 of the pump casing in relatively close running clearance relation therewith. The hub also includes a small diameter portion 46 projecting upwardly from the central part of the portion 45 and equipped with an arcuate concave outer surface 47, which extends for an appreciable distance above the throat 35.

The hub 45 is peripherally slotted or notched at 43 for a purpose to be hereinafter described.

Four circumferentially spaced flat teeth 49 radiate somewhat tangentially from the bottom end of the hub 45 to closely underlie the end Wall 32 of the impeller chamber 14. These teeth 49 converge to outer ends 4911 lying in a circle close to the top rim end 28 of the throat ring 24 in the impeller chamber 14. Each tooth 49, as shown in Figure 2, has a front leading edge 4% at the trailing end of a slot or notch 48. Each tooth 49 has a trailing inner end 496 at the forward edge of a slot or notch 48. Thus the inner ends of the teeth bridge the spaces between the slots 48 and extend outwardly from the ends of the slots.

As best shown in Figures 3, 4 and 5, a mixed flow pumping vane 50 depends from the leading edge of each tooth 49. A ring of pumping vanes is thereby provide-d around a central axial passage 51 in the impeller chamber 14. Each pumping vane 50 extends into relatively close proximity with the ledge or shoulder 27 of the throat ring 24 and with the tapered side wall 26 of the throat ring.

Each vane 56 has a helically pitched radially inner end portion and a generally tangential upstanding outer end portion connected therewith through an offset. The inner end portion has a substantially horizontal bottom leading end 50a closely overlying the throat ring rim or shoulder 27 and merging into an upstanding portion 50b which slopes backwardly and outwardly to the inner end of the tooth 49 from which the vane depends. The portion 50b" is joined through a radial shoulder or ledge 50:." with an upstanding centrifugal pumping vane portion 50d that extends tangentially to the outer end of the tooth 49' and'decreases in height as it approaches the outer end so as to have relatively close running clearance relationship with-the tapered sidewall 26 of the throatring 24. The upper ends of the vane portions 5% and Site merge into the rear ends of the slots 48 and these rear ends are inclined at 48a in the same manner as the upper ends of the vanes so as to provide, in effect, a continuation of the vane faces to the top of the teeth 49.

As best shown in Figure 5,, the fiat leading ends 50a of the vanes terminate in radial edges 50a. .These edges are arranged in diametrically opposite pair's'on the same diametric planes. The leading edges are preferably relatively sharp and, when the impeller is rotated in thedirection of the arrow, the edges slice into the liquid in the pump inlet to gradually accelerate the liquid axially upward and radially outward. The upstanding vane portions 5% at the inner ends of the vanes provide a substantially upward thrust on the liquid, causing it to flow toward the ports or slots 48, while the centrifugal force on the liquid created by the centrifugal pumping" vane portions causes the heavier liquid to; move outwardly away from the center 51. Thespaces between the inner end portions 50b of the vanes andthe pockets formed by the offset portions 50c of the vanes create vapor separating chambers which are vented at their upper ends by the slots 48.

The central chamber 51 of the impeller is therefore surrounded by vapor 'separating'chambers which, in turn, are vented at their upper ends. Centrifugal force tends to separate the vapor rich liquids from the fully liquid material with the lighter vaporrich material staying in the central portion of the impeller and'being forced under positive pressure due to the inclination of the vane faces 56b and 50b to the ports 48. The fully'liquid material is flung outwardly. by centrifugal force and is propelled by the pumping vanes 50d into the volute chamber 13 The upward thrust created on the material in the vapor separating chambers is continued by the inclined end walls 48a of the ports, causing the liquid to be positively discharged into the throat 35L Centrifugal force action (illustrated'by the arrows in Figs. land 3)- on liquid covering the throat 35 created by'the concave face 47 of the hub portion 46 produces a-current of liquid which sweeps across the gap inthe aperture 33 and upwardly along the throat wall to create a swirl chamber effect which tends to draw the vapor rich material into the current and'causes it to be discharged away from the pump. A circulation of liquid in the tank is thereby set up by the concave hubportion in the throat and this 'cur-v rent assists in the discharge of the vapor rich material out of the pump.

From the above descriptions it will therefore be understood that this invention provides a diffuser type vapor separating pump wherein ports or notches in the hub of a pump impeller coact with axial flow producing vanes onthe inside of the pump and with a current producing hub portion on the outside of the pump for discharging vapor rich materials out of the vapor separating chambers in the pump. The combined positive pressure discharge of the vapor rich material and the suction effect created by the induced current in the discharge throat of the pump tremendously'increase the pumping capacity of a diffuser type vapor separating pumpwithout increasing the pump load. Diffusion of the vapor rich material with the herein disclosed ethcient diffuser arrangement prevents the pump from becoming gas bound even when acting on liquids under pressures which are very close to the vapor pressures of even the main ingredients of the liquid. As a result, aircraft booster pumps according to this invention are adapted to maintain proper fuel feed at extremely high altitudes.

It will be understood that modifications and variations may be effected without departing from the scope of the novel concepts of the present invention.

I claim as my invention:

1. A difiuser type vapor separating pump comprising a pump casing having an open-ended impeller chamber with a pumping chamber therearound in communication therewith near one open end thereof, said casing having a diffuser throat diverging from said one open end of the impeller chamber to a mouth adapted to be submerged in liquid, an impeller having a ring of circumferentially spaced vanes in said impeller chamber adapted to receive liquid from the other end of the impeller chamber and centrifugally discharge said liquid into said pumping chamber, a first hub portion on said impeller in close running clearance relation with said one open end of the impeller chamber to provide a narrow gap relationship between the casing and said first hub portion, said impeller having a smaller diameter concave second hub portion extending from said first hub portion through said diffuser throat and diverging toward said first hub portion to create a current of fluid in the diffuser throat sweeping over the first hub portion across said narrow gap between said first hub portion and the pump casing and thence upwardly along the diverging throat wall, said first hub portion having a plurality of circumferential ports therethrough each aligned with a space between the impeller vanes, said vanes having relatively flat pitched fluid slicing leading ends at said other end of the impeller chamber and being axially and radially curved to upstanding walls defining vapor separating chambers therebetween vented through said ports to the diffuser throat, and said first and second hub portions coacting with said vanes to discharge vapor-rich fluids from the impeller chamber out of said diffuser throat.

2. A vapor separating pump comprising a casing defining an open-ended impeller chamber with an end wall adjacent one open end thereof having a circular opening therethrough and an annular pumping chamber surrounding the impeller chamber near said end wall in communication therewith around the entire impeller chamber, an impeller having a circumferentially ported hub portion projecting through the circular opening in said end wall in relatively close running clearance relationship therewith, a plurality of peripherally spaced teeth radiating from said hub portion in said impeller chamber adjacent said end wall, a vane depending from each tooth toward the other open end of the impeller chamber, each vane having a helical pitch with a flat leading end and an upstanding opposite end together with a radially ofiset upstanding tangentially trailing end decreasing in height toward the outer end thereof, said vanes defining vapor-separating chambers therebetween inwardly of said tangentially trailing ends thereof and vented through said ports to the outside of the casing, said end wall of the casing having a difiuser throat diverging from said circular opening to a larger diameter having a smaller diameter hub portion extending from said ported hub portion through said throat and curved to increase in diameter toward said ported hub portion for inducing a flow of fluid across the gap between the ported hub portion and the end wall of the casing and effective to coact with the vanes to discharge vapor-rich material through the ports in the hub portion and thereby prevent the pump from becoming gas-bound.

3. In a pump casing having an open-ended impeller chamber providing a pump inlet at a first open end and a diverging dilfuser throat at a second open end, both adapted to be submerged in liquid, said pump casing having a pumping chamber communicating with the periphery of the impeller chamber between the open ends of the impeller chamber, the improvement of a pump impeller having a shallow hub portion in close running clearance relationship with said second open end, a plurality of spaced outturned teeth on said hub in said impeller chamber, circumferentially spaced vanes each depending from a tooth, said vanes forming centrifugal separating chambers therebetween, said shallow hub por- 7 tion having a plurality of slots aligned with said separating chambers to vent the chambers through said second open end of the impeller chamber to said difiuser throat, said vanes each having a forward sloped leading surface extending from a scoop-like leading edge to the tooth on which the vane is mounted, and a rearwardly sloped face on the rear end of each hub slot extending upwardly from said vane whereby vapor-rich liquids from said separating chambers have a direct sloping path from the scoop-like leading edges of the vanes through the separating chambers to said diffuser throat at the outer faces of the slots.

4. In a diffuser type vapor separating pump having a casing with an open-ended impeller chamber equipped with a diffusion throat beyond a first open end of said chamber and diverging therefrom to an increased diameter mouth together with a pump inlet at a second open end of said impeller chamber and a pumping chamber surrounding the impeller chamber in communication therewith intermediate the open ends thereof, the improvement of an impeller in said impeller chamber having a hub with a first portion in close running cleareance gap relation with the first open end of the impeller chamber and a second hub portion extending through the diffusion throat, said second hub portion having an outwardly diverging surface eifective to sweep liquid across the gap between the first hub portion and the first open end of the impeller chamber and thence along the wall of said dilfusion throat, vanes on said impeller in said impeller chamber depending from said first portion of the hub and effective for pumping liquid from the second open end of the impeller chamber to said pumping chamber and for separating vapors from liquids in the impeller chamber, said first hub portion having ports for receiving vapors from said vanes, and said vanes coacting with said outwardly diverging surface on said second hub portion to diffuse vapors from the impeller chamber through said ports into the diffusion throat.

References Cited in the file of this patent UNITED STATES PATENTS 966,428 Comstock Aug. 9, 1910 1,211,767 Schroeder Jan. 9, 1917 2,392,128 Dinsmore Jan. 1, 1946 2,422,956 Edwards June 24, 1947 2,427,716 Curtis Sept. 23, 1947 2,660,120 Edwards Nov. 24, 1953 

